Refrigeration



c. E. PLOEGER ET AL 1,968,909

REFRIGERATION Filed Sept. 27, 1930 2 Sheets-Sheet l mum. "gnuunu,

INVENTORS. (Hyde E. Poegen BY Frank D Peirier' Aug. 7, 1934. c. E. PLOEGER ET AL REFRIGERATION Filed Sept. 27. 1950 2 Sheets-Sheet 2 INVENTORSA Clyde E. Ploeger. Frank D. Pehier' UNITED STATES PATENT OFFICE REFRIGERATION Clyde E. Ploeger and Frank D. Peltier, Evansville, Incl, assignors to Servel inc New York, N. "1., a corporation. Delaware Application September 27, 19%, serial No. 484,746 4 claims. (Cl. 62-126 This invention relates to a refrigerating system in a refrigerating system in which the liquid reof the compressor-condenser-expander type and frigcrant supply to the evaporator is controlled by more particularly to a means for returning lubria high side float valve; and

cant from the refrigerating element of the com- Fig. '7, a detail view of the wick in Fig. 4 modified pressor. In some refrigerating systems lubricant for use with a lubricant which stratifies below the 60 from the compressor mixes with the compressed refrigerant. refrigerant and passes through the condenser and Referring to the drawings, the header of an into the evaporator. Due to the relatively less evaporator of the flooded type is indicated at 1, a volatile nature of lubricants as compared with conduit 2 from the condenser, not shown, conrefrigerants, the latter pass from the evaporator veys liquid refrigerant to the evaporator where it 85 back to the compressor through the vapor suction is admitted through valve 3. Within the evaporaline, while the lubricant remains in the evaporator header is an open top or pan float 4 connected tor. In time accumulation of lubricant will be to operate valve 3 through bell crank 5 pivoted great enough to seriously impair the efficiency of at 6 and link 7 connected to valve member 8. As

the system and it will also be necessary to provide the level of the liquid 9 in the header rises float fresh lubricant to the compressor. In other-re- 4 rises and through the linkage just described frigerating systems lubrication of the compressor closes valve 3, and when the liquid level falls the is accomplished by using a so-called working fluid float operates to open valve 3,- thus admitting which consists of a refrigerant and a lubricant more fluid to maintain the liquid level substan- 20 which form a uniform mixture. In both of these tially constant. systems it is necessary to provide some means for Extending into the evaporator header 1 is a returning the lubricant from the evaporator to the vapor suction line 10 from the compressor which compressor. A very convenient method of doing terminates within the open top float 4 near the this is to introduce tlfe lubricant from the bottom thereof, as illustrated. Since the open 5 evaporator into the vapor suction line where it is top of the float communicates directly with the drawn along with the refrigerant vapor back to vapor space above the liquid in the evaporator, the compressor. vapor will be drawn into line 10 and returned to This invention contemplates a simple but posithe compressor. A wick 11 extends over the edge tive means'for effecting the transfer of lubricant of the pan float 4 with one .end depending into 30 into the vapor suction line where it can be drawn the liquid 9 and the other d ermi ating near back into the compressor. More specifically this the bottom of the pan float. Liquid from the invention contemplates the use of a capillary deevaporator will be carried through this wick by vice as, for instance, a wick for transferring lubricapillary action over the edge of and into the pan cant or a mixture of lubricant and refrigerant float from whence, after it has reached asumcient 35 from the evaporator into the vapor suction line level therein. it will be sucked into the vap r line t th compressor, 10 and returned along with the vaporized re- The invention will be more readily understood f i e 'a t0 the compressor. If the fluid 9 in t e by reference to the following description taken in evap rat i a mixture of refrigerant d u connection with the accompanying drawin s, in cant, some of the refrigerant will be evaporated 40 hi h from the mixture while going through the wick Fig. i is a horizontal section through an over the edg of the P and thus the liquid evaporator of the flooded type in which there is deposited within the D float will Contain 3 provided a lubricant return means contemplated greater Percentage of lubricant than the liquid by t invention; 1 in the evaporator. A small vent i5 is provided 45 Fig. 2 is a transverse section through the strucin line, 10 to pre e t q d in float 4 from p t shown in i 1; ing over to the compressor when it is not operat- Fig. 3, a vertical section of an evaporator showins.

ing a slightly modified arrangement of lubricant In Figs. 1 a d 2 a chamber 12 is partitioned Ofl return means; in the panfloat and the wick 11 transfers fluid 50 Fig. 4, a longitudinal vertical section of an into this chamber, whi h is p at the pevaporator of the flooded type showing a further stead of the liquid being Sucked l directly modification of this lubricant return means; through the p g in the 9 f vapor line 10, Fig. 5, a vertical section showing the lubricant a conduit 13 is provided which communicates at return means applied to an accumulator; one end with the suction lme at 14 and has its 65 Fig. 6, a diagrammatic view of the accumulator other end extending into the chamber 12 so that,

liquid transferred by wick 11 will be sucked up and carried into the flow of refrigerant vapor through line 10 back to the compressor. The chamber 12 is omitted in Fig. 3.

In Fig. 4 there is shown a modification of the previously described arrangements in which the evaporator header 1 is partitioned by a wall 16 which forms with the header casing a chamber 17 and a chamber 18 in open communication with each other at the top of the header over partition 16. Instead of the pan float, an ordinary float 19 is provided in chamber 17 to close valve 3 when the liquid 9 rises-above a pre-determined level, thus tending to maintain a substantially constant liquid level in chamber 17. On account of the partition 16 none of the liquid entering chamber 17 through valve 3 can enter chamber 18. The vapor suction line 10 extends into the header and terminates at a point near the bottom of chamber 18 as illustrated. The wick 11 extends from a point below the normal liquid level in chamber 17, over the partition 16, and depends into chamber 18, and effects a transfer of a portion of the fluid in chamber 17 into chamber 18 where itis sucked up into the vapor line 10 and returned to the compressor. Due to a certain amount of evaporation of the refrigerant in wick 11, the fluid transferred to chamber 18 will contain a relatively greater amount of lubricant than the fluid in chamber 1'7.

If a lubricant is used which does not mix with the refrigerant but stratifies, it is only necessary to extend the end of the wick 11 into the lubricant stratum in the evaporator. If the specific gravity of the lubricant is such that the refrigerant stratum is uppermost, as shown in Fig.

7, it will be necessary to suitably encase the wick 11 from a point above the normal liquid level to a point within the lubricant stratum with a material 20 impervious to the refrigerant. With such an arrangement only lubricant will be conveyed by the wick to the chamber 18 to be sucked up by the compressor.

An accumulator 22 is shown in detail in Fig. 5 and comprises an outer casing 25 which forms a chamber 26 with which an expansion coil communicates through conduit 27. In Fig. 6 there is shown diagrammatically an evaporator of the flooded type comprising expansion coils 21 and an accumulator 22. The admission of liquid refrigerant to the evaporator from conduit 23 is controlled by a high side float valve 24 which is well known in the art. A vapor suction line 28 from a compressor has an extension 31 project ing into chamber 26 which supports therein an open top vessel 29 by some convenient means as stud bolt 30 screwed into the end of the suction line extension 31 at 32 in such a manner that the suction line terminates near the bottom of vessel 29 and the upper edge of the open top vessel 29 is above the level of the inlet opening of conduit 2'7 from the expansion coils. Openings 33 near theend of the suction line extension 31 allow refrigerant vapor entering the accumulator from the expansion coils 21 to be withdrawn.

Any unevaporated refrigerant and lubricant entering the accumulator through conduit 2'7 will be balfled out and accumulate in chamber 26. A wick 34 extends from a point below the normal level of the liquid accumulation in chamber 26 and extends over the edge of vessel 29 and terminates at a point near the bottom thereof. Liquid from the chamber 26 will be carried over through wick 34 into the vessel 29 where it will be sucked up by the compressor along with vaporized refrigerant through openings 33 in the vapor suction line extension 31. Here also if a lubricant is used which does not mix with the refrigerant it is only necessary to extend the wick 34 into the lubricant strata to carry over only pure lubricant which will be sucked up along with the refrigerant vapor from within vessel 29.

It will be obvious to those skilled in the art that various other changes may be made in the construction and arrangement without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

We claim:

1. In a refrigerating system, an expansion chamber including a header, a refrigerant inletconduit, a control valve in said conduit, an open top hollow float responsive to the liquid level in said expansion chamber for operating said control valve, a vapor outlet conduit extending into said chamber and terminating within said float, and a wick extending from within said float to a point below the normal liquid level in said expansion chamber.

2. In a refrigerating system, an evaporator including a tubular header, an inlet conduit, a control valve in said conduit, a pan float responsive to the liquid level in said header for opening and 110 closing said valve, a vapor suction line extending into said evaporator and terminating within said pan float, and a capillary liquid transfer device extending from within said pan float to a point below the normal liquid level in said evaporator.

3. A refrigerating element including a-header, a liquid refrigerant conduit opening into said header, 9. control valve in said conduit, an open top hollow float responsive to the liquid level in said header for operating said valve, means within the float forming a chamber open at the top, a vapor suction line extending into said header and terminating within said float, a conduit extending from said vapor suction line and terminating within said chamber and means for transferring liquid from the evaporator into said chamher.

4. In a refrigerating system in which a fluid consisting of refrigerant and a lubricant soluble therein is circulated, an evaporator including a 130 tubular header, a fluid inlet conduit opening into said header, a valve in said conduit, a pan float responsive to the fluid level in said header, a partition in said pan flcat dividing the same into two compartments, a vapor suction line extending into said evaporator header and terminating within one of said compartments, a conduit extending from said line and terminating in the other of said compartments, a wick adapted to transfer fluid over the upper edge of said pan 140 float and into the last mentioned compartment.

CLYDE E. PLOEGER. FRANK D. PEL'I'IER. 

